Keep the focus of the topic.
Understand how Google sees the topic, Start at a high level with specific but generic words. Expand to sub-topics.
That also means exploring a range of topics, and looking at what "People Also Ask".
Build out proper keyword research.
(As an example, you could mistakenly start with your topic as "On Account" - only to discover that the proper topic is "Pay Monthly/Postpay", with the super-topic being "Mobile plans")

Are we matching a person's intent? What is that? Is it satisfying a need for information? Solving a problem? Fulfilling a need? How are you matching this intent?

Use customer language, avoid jargon and corporate language.
Use Natural Language Processing to enhance copy at every opportunity. This means using simple language that can be quickly understood.
Speak human.

Be as verbose as possible to describe the product, the use, the activity, the next steps.

Say what it is - as definitively and as naturally as possible, Think of a normal conversation to say exactly what it is, and what it is used for, or "what it means".

Explore further than just the "Buy, Buy, Buy" message.

Offer the pathway where customers take the next step.
There may be more than one.